This blog displays scenic photos taken from around Grand Marais, MI. Photos of rockhounding and nature adventures are also posted. Information is included about the Gitche Gumee Agate and History Museum and other scientific subjects. For more information about the museum and our unique mineral art, books, DVDs, and Online rockhounding classes please go to www.agatelady.com.

About Me

After more than a million miles of corporate travel, I moved to my family's home town of Grand Marais, MI in 1994. I now operate the Gitche Gumee Agate and History Museum as well as earn a living as a mineral artist and writer/designer. I hope that this blog will help me share my adventures and art with family, friends, museum patrons, and customers. You can learn more about the museum at www.agatelady.com.

Sunday, June 22, 2014

New NASA Images from Space

In the above photo the green-brown waters of Barkol Lake sit within the pale shorelines
of an ancient lake, hinting that the climate was once much wetter in
this part of western China. Today the region is arid and brown. Barkol
Lake’s annual mean precipitation is 210 millimeters (8 inches), while
the annual evaporation rate is 2,250 millimeters (89 inches). The desert
lake receives most of its water from runoff, and the water that remains
after evaporation is very salty and full of minerals. Square ponds on
the edge of the lake are probably evaporation ponds used to extract
those minerals from the water.

Astronauts on the International Space Station snapped this photo on
the lake on November 6, 2013. The astronauts were looking over the lake
from the west, so east is toward the top of the photograph. The basin is
closed, which means that the small streams in the photo run into the
lake, but nothing runs out. Evaporation is the only means through which
water leaves Lake Barkol.

The ancient shorelines show up as concentric rings, indicating that water levels have varied many times. One study
identified five climates at Barkol Lake over the past 8,000 years,
ranging from warm and wet to cold and wet and finally cold and dry. The
average annual temperature in the area is now just 1° Celsius (34° F),
though temperatures swing from extreme highs (33.5° C or 92.3° F) to
extreme lows (-43.6° C or -46.5° F).

The two photos above show the before and after appearance of an area in Colorado that experienced a huge land slide.

On Sunday, May 25, 2014, a large mudslide rushed down a Colorado
mountain near the town of Collbran covering an area three miles long and
one-half to three-quarters of a mile wide. It claimed the lives of
three ranchers and triggered a small earthquake.

The extent of the mudslide is evident in the top image, which was
acquired by the Landsat 8 satellite on June 7. The lower image, taken by
Landsat 8 on June 20, 2013, shows the slide region before the slide.
The top edge of the slide, the scarp, is on the lower side of the image.
The debris flowed north and ended at the toe, partially covering a
natural gas well.
The slide happened in the Grand Mesa region of western Colorado, an
area extremely prone to landslides. In fact, the recent mudslide began
at the scarp of a previous landslide. The region is unstable because of
its underlying geology.
A layer of basalt lies on top of soft claystone that erodes easily. The
basalt slumps when water erodes the soft rock beneath it, as
illustrated in this diagram:

Landslides are most prevalent in this region during the spring and
early summer when the ground is moist from snow melt and runoff.

On average, Colorado experiences thousands of landslides every year. According to the Colorado Landslide Inventory, most of the slides occur in the mountainous western half of the state.

To the human eye, the wind is invisible. It can only be visualized by
proxy, by its expressions in other natural phenomena like blowing
leaves, airborne dust, white-capped waters—or the patterns of clouds.

Cumulus cloud streets trace the direction, and sometimes the
intensity, of winds. As puffy cumulus clouds form in the warmth of
morning sunlight, they line up parallel to the direction of the wind.
Often this means a straight line, as seen in the winter when cold winds blow over warmer waters, as shown in the NASA image below of the Great Lakes.

But clouds can also line up along the concentric, curved lines of high-pressure weather systems. The image above of Brazil was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua
satellite on June 5, 2014. It shows a broad swath of the Amazon
rain forest in Brazil and Bolivia as it appeared in the early afternoon
(1:20 p.m. local time or 1720 Universal Time).

“Convective cloud streets form during the day due to heating of the
land, often over fairly flat surfaces,“ wrote Patrick Minnis, a cloud
researcher at NASA’s Langley Research Center.
As sunlight warms the Amazon rain forest in the morning, water vapor
rises on columns of heated air (thermals). When that humid air runs into
a cooler, more stable air mass above, it condenses into fluffy cumulus
clouds that can line up with the prevailing winds. “The clouds form in
the morning and die out in the afternoon as the surface heating
diminishes. They are very common over the United States during summer.

Kristopher Bedka, another Langley cloud researcher, examined a
numerical weather prediction model to find the wind direction near the
top of the boundary layer on June 5. “There appeared to be a
high-pressure center in southeast Brazil causing the air flow to move
counterclockwise around the center,” he noted. “The cloud streets
aligned almost perfectly with the wind flow.”